The present invention relates to packages for opto-electrical components, the term xe2x80x9copto-electrical componentsxe2x80x9d being used herein to designate in general those circuits, assemblies or sub-assemblies comprising electrical, optical as well as optoelectronic (e.g., photodetectors, laser sources, etc.) devices. Exemplary of such packages are transmitter/receiver packages for optical transmission systems.
Such packages must in general comply with a number of requirements which are at least partly conflicting among them. For instance, the package structure should provide all the external constant electrical connections both at radio frequency (RF) and DC, and optical feed-through, as well as mechanical protection. Flexibility in the internal layout is also an extensively felt need, in that such a layout should be preferably chosen depending on the configuration of components to be included in the device. Electrical connections should be ensured with a high degree of reliability, the same also applying to the mechanical structure of the package. Finally, assembling the package should be easy, leaving a reasonable degree of freedom of movement.
Such requirements do not appear to be satisfactorily met by prior art package solutions which generally are provided for a fixed design.
This applies particularly to providing the so-called optical feed-through when ceramic materials are used for the structure of the casing of the package.
In fact, when package frames of a metal material are used (as shown e.g. in U.S. Pat. No. 6,220,765), the optical feed-through is simply provided by an aperture or hole in one of the metal walls of the package.
Conversely, when ceramic materials, such as alumina, are used for the package and, more to the point, when layered ceramic material technology is used for the package, a limitation may arise in respect of the size, shape and location of the optical feed-through.
The object of the present invention is thus to provide an improved solution overcoming the disadvantage outlined in the foregoing.
According to the present invention, a package for opto-electrical components comprises a casing including a housing chamber for the opto-electrical components, wherein the casing has an opening that defines an optical feed-through path between the chamber and the casing exterior. The casing includes a ceramic material at least in the vicinity of the opening. An adapter associated with the opening has an aperture for accepting at least one of a fiber pigtail or a fiber optic connector. Preferably, the opening has a parallelogram shape and the aperture is substantially circular.
The adapter preferably includes metal material and is brazed to the casing. The adapter preferably includes at least one portion adaptively fitting into the parallelogram-shaped opening.
At least one board or tile adapted to be housed in the chamber of the casing carries the components. A photodetector and a first amplifier stage associated with the photodetector are preferably mounted on the silicon optical bench that is carried by the at least one board or tile.
The optical bench is preferably provided with electrical tracks at its underside. The casing preferably includes a ceramic base member having via-holes.
A transimpedance amplifier and a post amplifier are preferably carried by the board or tile. The transimpedance amplifier and post amplifier are connected by a capacitor that is connected via direct bonding to at least one of the transimpedance amplifier and the post amplifier. The at least one bonding is preferably associated with the components and covered with an impedance-matching glue.
At least one board or tile adapted to be housed in the chamber of the casing carries said components which are attached by glueing to at least one board or tile.
The above and still further objects, features and advantages of the present invention will become apparent upon consideration of the following detailed descriptions of one specific embodiment thereof, especially when taken in conjunction with the accompanying drawings.